The Clinical Trials Statistical and Data Management Center (CTSDMC) in the Department of Biostatistics, College of Public Health at The University of Iowa in collaboration with the Department of Internal Medicine proposes to establish and operate the Data Coordinating Center (DCC) for the Clinical Islet Transplantation: Data Coordinating Center (RFA -DK-04-004). This CTSDMC will work with the study clinical centers, and NIH to develop and execute important clinical investigations to help address the consortium's goals to develop and execute important mechanistic and clinical investigations to understand and improve islet cell transplantation in patients with type I diabetes. We will use our study design, statistical, data management, and study coordination experience and expertise to help the consortium examine ways to (1) increasing the efficiency of islet transplantation; (2) improving immunotherapy to reduce toxicity, recurrent autoimmunity and allograft rejection; and (3) to develop interventions to reduce the local complications of the islet administration procedure. Our group brings over 30 years of experience in the design and implementation clinical and epidemiology studies and over 14 years experience serving as the data coordinating center for multi-center clinical trials. These studies include studies in neurology, nephrology, and diabetes. We represent an experienced and productive team of investigators who have worked together for many years. The CTSDMC staff has; successfully developed and operated web based data entry systems and databases for multi-center trials and have an excellent record in successfully coordinating clinical trials.